1. Field of the Invention
The invention relates to a cup-shaped container of plastics material of a substantially conical basic shape having a wall and a base which can be pressed out in the direction of the longitudinal axis of the container and in particular can be moved from a first end position into a second end position and vice versa, and having an edge part with a contact edge projecting downwards beyond the base.
2. Prior Art
Known containers of this type are used for example for holding dairy products, dessert preparations and the like and are closed after pouring in the substance to be packed. In this connexion the closure can, in particular, be in the form of a foil which consists of metal and/or plastics material and which can be secured to an upper rim of the container by sealing, adhesion or the like. In addition, there are also other possibilities for closing the filled container. In containers of this type which are used for packaging, a stacking edge or shoulder is frequently provided on the upper end thereof below the rim on which the closure foil is to be laid, but it can also be provided at another point, for example in the lower region.
Certain pourable substances, for example fruit preparations, desserts or the like are poured in a hot state. Since the container in question is closed immediately after filling, an underpressure subsequently arises in the closed container as a result of the cooling of the poured substance and possibly also caused by working of the later. On the other hand, there are also pourable substances which produce gases or whose volume increases to a certain extent after the container has been filled and sealed, as a result of which an overpressure is then produced in the sealed container. Both an overpressure of this type and an underpressure can have an adverse effect and lead to tearing of the closure, to buckling of the walls or to damage to the container.
In order to take account of this, containers have been proposed with deflectable bases. In a known embodiment of a cup (German Gebrauchsmuster 73 12 456) the base has concentric circular raised and recessed portions, so that a corrugated profile in the radial cross-section is produced, in order to form a deformable diaphragm. In this connexion the occurrence of uncontrolled or undesired deformations or displacements of the base of the cup cannot always be prevented. In addition, containers are known having a smooth base curved in a spherical shape which can be made to revert from one position to another in the manner of a snapping action. This, however, demands the application of a certain amount of force and requires a relatively robust construction of the base.